vfio-iommufd: Add detach_ioas support for emulated VFIO devices

This prepares for adding DETACH ioctl for emulated VFIO devices.

Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Tested-by: Terrence Xu <terrence.xu@intel.com>
Tested-by: Nicolin Chen <nicolinc@nvidia.com>
Tested-by: Matthew Rosato <mjrosato@linux.ibm.com>
Tested-by: Yanting Jiang <yanting.jiang@intel.com>
Tested-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
Tested-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Signed-off-by: Yi Liu <yi.l.liu@intel.com>
Link: https://lore.kernel.org/r/20230718135551.6592-16-yi.l.liu@intel.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

8 files changed, 22 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c
index de675d799c7d..9cd9e9da60dd 100644
--- a/drivers/gpu/drm/i915/gvt/kvmgt.c
+++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
@@ -1474,6 +1474,7 @@ static const struct vfio_device_ops intel_vgpu_dev_ops = {
 	.bind_iommufd	= vfio_iommufd_emulated_bind,
 	.unbind_iommufd = vfio_iommufd_emulated_unbind,
 	.attach_ioas	= vfio_iommufd_emulated_attach_ioas,
+	.detach_ioas	= vfio_iommufd_emulated_detach_ioas,
 };
 
 static int intel_vgpu_probe(struct mdev_device *mdev)
diff --git a/drivers/s390/cio/vfio_ccw_ops.c b/drivers/s390/cio/vfio_ccw_ops.c
index 5b53b94f13c7..cba4971618ff 100644
--- a/drivers/s390/cio/vfio_ccw_ops.c
+++ b/drivers/s390/cio/vfio_ccw_ops.c
@@ -632,6 +632,7 @@ static const struct vfio_device_ops vfio_ccw_dev_ops = {
 	.bind_iommufd = vfio_iommufd_emulated_bind,
 	.unbind_iommufd = vfio_iommufd_emulated_unbind,
 	.attach_ioas = vfio_iommufd_emulated_attach_ioas,
+	.detach_ioas = vfio_iommufd_emulated_detach_ioas,
 };
 
 struct mdev_driver vfio_ccw_mdev_driver = {
diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index b441745b0418..2d3c3a79b687 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -1975,6 +1975,7 @@ static const struct vfio_device_ops vfio_ap_matrix_dev_ops = {
 	.bind_iommufd = vfio_iommufd_emulated_bind,
 	.unbind_iommufd = vfio_iommufd_emulated_unbind,
 	.attach_ioas = vfio_iommufd_emulated_attach_ioas,
+	.detach_ioas = vfio_iommufd_emulated_detach_ioas,
 	.request = vfio_ap_mdev_request
 };
 
diff --git a/drivers/vfio/iommufd.c b/drivers/vfio/iommufd.c
index 86df5415759a..4d84904fd927 100644
--- a/drivers/vfio/iommufd.c
+++ b/drivers/vfio/iommufd.c
@@ -231,3 +231,16 @@ int vfio_iommufd_emulated_attach_ioas(struct vfio_device *vdev, u32 *pt_id)
 	return 0;
 }
 EXPORT_SYMBOL_GPL(vfio_iommufd_emulated_attach_ioas);
+
+void vfio_iommufd_emulated_detach_ioas(struct vfio_device *vdev)
+{
+	lockdep_assert_held(&vdev->dev_set->lock);
+
+	if (WARN_ON(!vdev->iommufd_access) ||
+	    !vdev->iommufd_attached)
+		return;
+
+	iommufd_access_detach(vdev->iommufd_access);
+	vdev->iommufd_attached = false;
+}
+EXPORT_SYMBOL_GPL(vfio_iommufd_emulated_detach_ioas);
diff --git a/include/linux/vfio.h b/include/linux/vfio.h
index f2f02273ece1..24091a7c7bdb 100644
--- a/include/linux/vfio.h
+++ b/include/linux/vfio.h
@@ -128,6 +128,7 @@ int vfio_iommufd_emulated_bind(struct vfio_device *vdev,
 			       struct iommufd_ctx *ictx, u32 *out_device_id);
 void vfio_iommufd_emulated_unbind(struct vfio_device *vdev);
 int vfio_iommufd_emulated_attach_ioas(struct vfio_device *vdev, u32 *pt_id);
+void vfio_iommufd_emulated_detach_ioas(struct vfio_device *vdev);
 #else
 static inline struct iommufd_ctx *
 vfio_iommufd_device_ictx(struct vfio_device *vdev)
@@ -157,6 +158,8 @@ vfio_iommufd_get_dev_id(struct vfio_device *vdev, struct iommufd_ctx *ictx)
 	((void (*)(struct vfio_device *vdev)) NULL)
 #define vfio_iommufd_emulated_attach_ioas \
 	((int (*)(struct vfio_device *vdev, u32 *pt_id)) NULL)
+#define vfio_iommufd_emulated_detach_ioas \
+	((void (*)(struct vfio_device *vdev)) NULL)
 #endif
 
 static inline bool vfio_device_cdev_opened(struct vfio_device *device)
diff --git a/samples/vfio-mdev/mbochs.c b/samples/vfio-mdev/mbochs.c
index c6c6b5d26670..3764d1911b51 100644
--- a/samples/vfio-mdev/mbochs.c
+++ b/samples/vfio-mdev/mbochs.c
@@ -1377,6 +1377,7 @@ static const struct vfio_device_ops mbochs_dev_ops = {
 	.bind_iommufd	= vfio_iommufd_emulated_bind,
 	.unbind_iommufd	= vfio_iommufd_emulated_unbind,
 	.attach_ioas	= vfio_iommufd_emulated_attach_ioas,
+	.detach_ioas	= vfio_iommufd_emulated_detach_ioas,
 };
 
 static struct mdev_driver mbochs_driver = {
diff --git a/samples/vfio-mdev/mdpy.c b/samples/vfio-mdev/mdpy.c
index a62ea11e20ec..064e1c0a7aa8 100644
--- a/samples/vfio-mdev/mdpy.c
+++ b/samples/vfio-mdev/mdpy.c
@@ -666,6 +666,7 @@ static const struct vfio_device_ops mdpy_dev_ops = {
 	.bind_iommufd	= vfio_iommufd_emulated_bind,
 	.unbind_iommufd	= vfio_iommufd_emulated_unbind,
 	.attach_ioas	= vfio_iommufd_emulated_attach_ioas,
+	.detach_ioas	= vfio_iommufd_emulated_detach_ioas,
 };
 
 static struct mdev_driver mdpy_driver = {
diff --git a/samples/vfio-mdev/mtty.c b/samples/vfio-mdev/mtty.c
index a60801fb8660..5af00387c519 100644
--- a/samples/vfio-mdev/mtty.c
+++ b/samples/vfio-mdev/mtty.c
@@ -1272,6 +1272,7 @@ static const struct vfio_device_ops mtty_dev_ops = {
 	.bind_iommufd	= vfio_iommufd_emulated_bind,
 	.unbind_iommufd	= vfio_iommufd_emulated_unbind,
 	.attach_ioas	= vfio_iommufd_emulated_attach_ioas,
+	.detach_ioas	= vfio_iommufd_emulated_detach_ioas,
 };
 
 static struct mdev_driver mtty_driver = {